Introducing UNDR TMB1
The Ulster & Northern Dutchess Readiness Group enjoys many activities in the field to improve practical communication skills. Our first official product series for UNDR Groupcalled the UNDR TMB1 and is our universal tape measure beam component and build plans for making a variety of useful antennae.
Key Design Thoughts:
|
|
Official Design Version Variants
TMB1-440 - Our 5 element Yagi design fills a number of needs around UHF spectrum above and below the amateur 70cm band and it weights less than 1/2 pound (0.25 kilogram) when assembled as pictured. Our build plans are optimized for 439.7 MHz, which is the third harmonic of 146.565, which is common for radio direction finding.
The TMB1-440 can be used for pretty much any amateur radio activity requiring a high gain, small size antenna with good front/back ratio involving the 70cm spectrum.
Other use cases below or above the amateur radio spectrum are possible too from 401 to 470 MHz such as NOAA balloons, GMRS and ISM applications where permitted. Below is an averaged S11 return loss from 5 constructed antenna to show the repeatability of this antenna design.
The TMB1-440 can be used for pretty much any amateur radio activity requiring a high gain, small size antenna with good front/back ratio involving the 70cm spectrum.
Other use cases below or above the amateur radio spectrum are possible too from 401 to 470 MHz such as NOAA balloons, GMRS and ISM applications where permitted. Below is an averaged S11 return loss from 5 constructed antenna to show the repeatability of this antenna design.
- TMB1-440 Parts Shopping List
- TMB1-440 Build Instructions
- TMB1-440 Online Purchase Page (Available early 2026)
TMB1-220 - Our 4 element Yagi design focused on the less used 220 MHz band can be used as a low cost, high gain antennae to reach distant repeaters or summits on the air contacts. If your area has any WinLink, BBS or other data focused opportunities, the TMB1-220 makes a great antenna that works great at home or in the field while weighing less than 1/2 pound (0.25 kilogram). This design is optimized for 223,5 MHz and has coverage far exceeding the amateur 1.25m band, should you wish to use this for other activities.
- TMB1-220 Parts Shopping List
- TMB1-220 Build Instructions (Available early 2026)
- TMB1-220 Purchase Page (Available early 2026)
Versions In Development
TMB1-50 - This will be our two element highly portable 6m band version great for summits on the air activity. Available early 2026
TMB1-144 - This will be our two element Yagi optimized for radio direction finding activities in the amateur 2m 144-148 MHz spectrum band along with other use cases. Available early 2026
TMB1-SAT4ME - This will be our dual band 2m/70cm extreme light weight satellite antenna with driven elements for 2m band and parasitic elements for the 70cm band. Available early 2026